<template>
  <div class="goods-sku">
    <dl v-for="item in goods.specs" :key="item.id">
      <dt>{{ item.name }}</dt>
      <dd>
        <template v-for="val in item.values" :key="val.name">
          <img :class="{ selected: val.selected, disabled: val.disabled }" @click="clickSpecs(item, val)"
            v-if="val.picture" :src="val.picture" />
          <span :class="{ selected: val.selected, disabled: val.disabled }" @click="clickSpecs(item, val)" v-else>{{
              val.name
          }}</span>
        </template>
      </dd>
    </dl>
  </div>
</template>
<script setup name='XtxGoodSku'>
import { watchEffect } from 'vue'
import getPowerSet from './power-set'
  const spliter = '★'
  // 根据skus数据得到路径字典对象
  const getPathMap = (skus) => {
    const pathMap = {}
    if (skus && skus.length > 0) {
      skus.forEach(sku => {
        // 1. 过滤出有库存有效的sku
        if (sku.inventory) {
          // 2. 得到sku属性值数组
          const specs = sku.specs.map(spec => spec.valueName)
          // 3. 得到sku属性值数组的子集
          const powerSet = getPowerSet(specs)
          // 4. 设置给路径字典对象
          powerSet.forEach(set => {
            const key = set.join(spliter)
            // 如果没有就先初始化一个空数组
            if (!pathMap[key]) {
              pathMap[key] = []
            }
            pathMap[key].push(sku.id)
          })
        }
      })
    }
    return pathMap
  }

  // 初始化禁用状态
  function initDisabledStatus (specs, pathMap) {
    if (specs && specs.length > 0) {
      specs.forEach(spec => {
        spec.values.forEach(val => {
          // 设置禁用状态
          val.disabled = !pathMap[val.name]
        })
      })
    }
  }

  // 得到当前选中规格集合
  const getSelectedArr = (specs) => {
    const selectedArr = []
    specs.forEach((spec, index) => {
      const selectedVal = spec.values.find(val => val.selected)
      if (selectedVal) {
        selectedArr[index] = selectedVal.name
      } else {
        selectedArr[index] = undefined
      }
    })
    return selectedArr
  }

  // 更新按钮的禁用状态
  const updateDisabledStatus = (specs, pathMap) => {
    // 遍历每一种规格
    specs.forEach((item, i) => {
      // 拿到当前选择的项目
      const selectedArr = getSelectedArr(specs)
      // 遍历每一个按钮
      item.values.forEach(val => {
        if (!val.selected) {
          selectedArr[i] = val.name
          // 去掉undefined之后组合成key
          const key = selectedArr.filter(value => value).join(spliter)
          val.disabled = !pathMap[key]
        }
      })
    })
  }

  const props = defineProps({
    // specs:所有的规格信息  skus:所有的sku组合
    goods: {
      type: Object,
      default: () => ({ specs: [], skus: [] })
    }
  })

  const emit = defineEmits(['change'])
  
  let pathMap = {}
  watchEffect(() => {
    // 得到所有字典集合
    pathMap = getPathMap(props.goods.skus)
    // 组件初始化的时候更新禁用状态
    initDisabledStatus(props.goods.specs, pathMap)
  })

  const clickSpecs = (item, val) => {
    if (val.disabled) return false
    // 选中与取消选中逻辑
    if (val.selected) {
      val.selected = false
    } else {
      item.values.forEach(bv => { bv.selected = false })
      val.selected = true
    }
    // 点击之后再次更新选中状态
    updateDisabledStatus(props.goods.specs, pathMap)
    // 把选择的sku信息传出去给父组件
    // 触发change事件将sku数据传递出去
    const selectedArr = getSelectedArr(props.goods.specs).filter(value => value)
    // 如果选中得规格数量和传入得规格总数相等则传出完整信息(都选择了)
    // 否则传出空对象
    if (selectedArr.length === props.goods.specs.length) {
      // 从路径字典中得到skuId
      const skuId = pathMap[selectedArr.join(spliter)][0]
      const sku = props.goods.skus.find(sku => sku.id === skuId)
      // 传递数据给父组件
      emit('change', {
        skuId: sku.id,
        price: sku.price,
        oldPrice: sku.oldPrice,
        inventory: sku.inventory,
        specsText: sku.specs.reduce((p, n) => `${p} ${n.name}：${n.valueName}`, '').trim()
      })
    } else {
      emit('change', {})
    }
  }

</script>

<style scoped lang="scss">
@mixin sku-state-mixin {
  border: 1px solid #e4e4e4;
  margin-right: 10px;
  cursor: pointer;

  &.selected {
    border-color: $xtxColor;
  }

  &.disabled {
    opacity: 0.6;
    border-style: dashed;
    cursor: not-allowed;
  }
}

.goods-sku {
  padding-left: 10px;
  padding-top: 20px;

  dl {
    display: flex;
    padding-bottom: 20px;
    align-items: center;

    dt {
      width: 50px;
      color: #999;
    }

    dd {
      flex: 1;
      color: #666;

      >img {
        width: 50px;
        height: 50px;
        margin-bottom: 4px;
        @include sku-state-mixin;
      }

      >span {
        display: inline-block;
        height: 30px;
        line-height: 28px;
        padding: 0 20px;
        margin-bottom: 4px;
        @include sku-state-mixin;
      }
    }
  }
}
</style>